Hesitation/Stumble Issue

[Snoopy48]

Hey guys. Need some help. I have a 2013 RAM 1500, 5.7. It has approx. 64K miles. This past weekend I changed the plugs and they needed it. However, the reason I changed them besides it being time based on miles, I am getting a VERY slight hesitation/stumble during acceleration. It is most noticeable to me when shifting from 2nd to 3rd gear and all the way through 3rd gear. To better describe it, let's say your accelerating from a stop light. you feel the truck shifting 1st to 2nd and as it shifts to 3rd you feel a slight wind gust hitting you head on sparactically. Once I am into 4th, 5th & 6th gears it is not as bad. However, while holding a steady speed on flat road, if i hit a slight incline, I can feel the VERY VERY slight hesitation again. It seems that it is happening under a load like maybe a coil pack is breaking down or something.

Now, some of you will say "if it's so SLIGHT whats the big deal"? Well, something is wrong and it bugs the SH_T out of me every time I drive it. I will say this. When I switch to tow/haul mode if it does do it, I cannot feel it. So, what would switching to tow/haul mode do with a problem like this? Could it be an MDS issue?

There are no codes and the dealer "claims" the transmission is working perfectly so what should I check next. There are no fuel filters on these trucks so that can't be the issue. I cleaned the throttle body butterfly & housing really good. After the plug change, this thing does run 100 times better at idle than before changing the plugs but it didn't help the hesitation issue.

 

[MADDOG]

It was a good idea to change the plugs. If you aren't getting a check engine light, but still getting a stumble I'd recommend you check a few things:

1. Remove the air intake pipe to the throttle body and check the TB. It may be really dirty and gummed up, which causes what you are experiencing.

2. Check your EGR valve. Normally this throws a code but a partially blocked or malfunctioning EGR can also cause driveability issues. Replace the valve if it appears to be partially or fully blocked by carbon deposits. It also helps to use a bit of compressed air to blow out the lines leading to it.

3. Replace your PCV valve.

 

[Snoopy48]

It was a good idea to change the plugs. If you aren't getting a check engine light, but still getting a stumble I'd recommend you check a few things:

1. Remove the air intake pipe to the throttle body and check the TB. It may be really dirty and gummed up, which causes what you are experiencing.

2. Check your EGR valve. Normally this throws a code but a partially blocked or malfunctioning EGR can also cause driveability issues. Replace the valve if it appears to be partially or fully blocked by carbon deposits. It also helps to use a bit of compressed air to blow out the lines leading to it.

3. Replace your PCV valve.

NICE! I will follow up on these suggestions. I did clean the throttle body as good as I could get it. However, I have not yet checked the PCV valve nor the EGR. I'm sure they could stand a good cleaning at the very least.

Thanks!

 

[MADDOG]

Let us know how things go.

 

[Snoopy48]

Certainly will, thanks.

 

[countrygunner]

So the plug wires can cause issues to when a load shows up a spark issue will be noticeable. However it’s usually more of a miss.

I’d say it’s more of a emissions issue like stated above.

 

[Fitz-0518]

My experience with condition you stated is as others have suggested. Suspect that plug wires are breaking down under load. If after following the suggestions, you still have a low grade idle miss, check your O2 sensors. With the right type of scanner you can compare what it is doing versus factory specs. The intake O2 may be the hardest working part on our trucks. Like you, I can not tolerate engine missing or a trans not shifting properly. My experience with 4 5.7's, they can and will idle and run super smooth.

 

[Snoopy48]

Hey guys. Thanks for all your input. Yesterday I got a can of Mass Airflow Spray Cleaner. I removed the intake duct and cleaned the MAS as directed. I am either wishing too much OR doing that actually improved the problem. I have a 25 minute commute to work everyday and only 1-2 times did I feel anything and even then it was not near as bad as it has been doing. So, I'm going to go ahead and replace the PCV and EGR to hopefully get rid of any remaining issues.

Could just cleaning the MAS really make that much of a difference? I thought typically with a MAS the engine will either run or not run.

 

[grizzstang]

It could definitely be a COP (coil over plug) on its way out. It is called a low grade misfire. It doesn't set a check engine light but it still may have set a code. How did the boots look on the coils? Any cracks? Did you use some dielectric grease in them?

 

[RysRam]

Hey guys. Thanks for all your input. Yesterday I got a can of Mass Airflow Spray Cleaner. I removed the intake duct and cleaned the MAS as directed. I am either wishing too much OR doing that actually improved the problem. I have a 25 minute commute to work everyday and only 1-2 times did I feel anything and even then it was not near as bad as it has been doing. So, I'm going to go ahead and replace the PCV and EGR to hopefully get rid of any remaining issues.

Could just cleaning the MAS really make that much of a difference? I thought typically with a MAS the engine will either run or not run.

5.7 Hemi doesn't have a mass air sensor....they use a speed/density system that relies primarily on a MAP sensor. You may have just hosed down your intake temp sensor.

 

[Snoopy48]

It could definitely be a COP (coil over plug) on its way out. It is called a low grade misfire. It doesn't set a check engine light but it still may have set a code. How did the boots look on the coils? Any cracks? Did you use some dielectric grease in them?

Yes, same grease and they looked brand new to me. No cracking, damage or anything obvious.

 

[Snoopy48]

5.7 Hemi doesn't have a mass air sensor....they use a speed/density system that relies primarily on a MAP sensor. You may have just hosed down your intake temp sensor.

Ahhh, it is the sensor inside the intake air duct and has a tiny blue tip on it. It looked really clean before I sprayed it.

 

[RysRam]

Ahhh, it is the sensor inside the intake air duct and has a tiny blue tip on it. It looked really clean before I sprayed it.

Yep, that's the intake air temp sensor.

 

[Snoopy48]

Yep, that's the intake air temp sensor.

So, I guess that was a waste of time cleaning? LOL

 

[RysRam]

So, I guess that was a waste of time cleaning? LOL

Meh, at least it's extra clean now lol.

You can also try looking for any broken or unplugged vacuum fittings/lines next time you're under the hood. Most of them will be on the driver's side.

 

[Snoopy48]

Meh, at least it's extra clean now lol.

You can also try looking for any broken or unplugged vacuum fittings/lines next time you're under the hood. Most of them will be on the driver's side.

Will do. Thanks

So, could cleaning that sensor have made a difference with hesitation issue?

 

[Snoopy48]

Well, I am really getting more and more irritated with this hesitation/misfire, stumble or whatever the h_ll it is. I have fined tuned it down to it being the most obvious when under a load such as taking off and hitting a incline while at cruising speeds. I have tried the "magic shift selector" formula to turn off MDS, changed plugs, cleaned the intake air sensor (by mistake), and tried Seafoam. Nothing works. I have a PCV valve on order from RockAuto but I really don't expect that to solve the problem. I have been reading quite a lot online about guys having the exact same described issue I am and it seems too many of them have turned out to be flat camshaft lobe on cylinder #3. So, I'm not feeling too warm and fuzzy about this problem right now. Like most of us, I cannot afford to let a mechanic run up huge bill trying to catch and corner this troll that's under the hood. Equally the same, I cannot afford to trow parts at it hoping something will magically solve the issue. So, needless to say I find myself in a not so happy place with this truck right now. I will install the new PCV valve when it comes in and report back but if that does not magically fix the issue I will more than likely will be looking to trade out of it.

It astonishes me (although it shouldn't) that Dodge has not, will not, or does not want to either address or find the problem to these misfire issues and then render a solution to where the consumer doesn't have to bear the burden of the cost to actually get it fixed. There are WAYYYYY too many guys having the same issues I am with these trucks.

 

[SYKRAMMAN]

You should pop off your valve covers and have a peak.

 

[Snoopy48]

You should pop off your valve covers and have a peak.

Yeah, I might try that this weekend. Good idea.

 

[grizzstang]

My money is still on a bad coil.